32 or 64 bit Windows 7?

So I don't really know crap about the difference, but I am upgrading my ram to 4gigs and I hear 64 bit OS better utilizes large amounts of ram such as the numbers I will be reaching shortly. I am picking up Windows 7 for $30 through some uni offer, and it is giving me the option of purchasing either one. Should I bother going through the effort of setting up a 64 bit OS?

_________________“If you want to make an apple pie from scratch, you must first create the universe.”-- Carl Sagan